Additive for hydrocarbon fuel consisting of non-acidic inorganic compounds of boron and related processes

ABSTRACT

The present invention provides a fuel additive and a process for using and making the fuel additive. The fuel additive includes a non-acidic boron-containing salt in a carrier fluid. The fuel additive enhances combustion by increasing fuel efficiency or decreased pollutant output in an exhaust gas resulting from combustion of the fuel with the fuel additive.

RELATED APPLICATIONS

This application is related to and claims priority and benefit of U.S.Provisional Patent Application Ser. No. 60/673,907, filed Apr. 22, 2005,titled “Additive For Hydrocarbon Fuel Consisting of Non-Acidic InorganicCompounds of Boron and Related Processes,” which is incorporated hereinby reference in its entirety.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to the field of fuel additives, and inparticular, to a boron-containing additive for hydrocarbon fuels used toenhance efficiency and/or reduce pollution.

BACKGROUND OF THE INVENTION

Many hydrocarbon fuels have been used, each with its own advantages anddrawbacks. Examples of such fuels include gasoline, natural gas, diesel,kerosene, jet fuel, LPG, heavy distillates, bunker fuel, ethanol, coal,other solid hydrocarbon fuels and the like. Chemical compounds have beenused as fuel additives over the past century to improve variousparameters, such as octane number, of various fuels. The use, andsubsequent banning, of lead in gasoline has been known for a long time.Tetraethyl lead showed a positive effect on octane and a profoundlynegative effect on the environment.

In addition to tetraethyl lead, several elements are known to havecombustion catalyst characteristics in gasoline or other hydrocarbonfuels. Examples, in addition to lead, are manganese, iron, copper,cerium, calcium and barium. Each of these elements has advantages anddisadvantages in particular applications. Drawbacks of certain ironcompounds include limited solubility in gasoline, toxicity, and expenseas an additive. Interaction with sulfur and creation of sulfideprecipitate may also occur, which is undesirable.

Another commonly-used additive in gasoline is MTBE. While this compoundboosts octane levels significantly, the compound is thought to becarcinogenic. Also, it mixes easily with water which is hazardous shouldthere be a leak. Gasoline containing MTBE leaking from an undergroundtank at a gas station could potentially leach into groundwater andcontaminate wells. As a result of the believed negative potential effectof MTBE on the environment, ethanol is also being evaluated as agasoline additive to boost octane.

In addition to the industry goal of improved combustion efficiency,reduction of smoke and particulate emissions is also a concern,particularly for diesel fuel applications. The industry has not madesubstantial progress on development of a fuel additive for reducingsmoke and particulate emissions.

Finally, adjustment of combustion parameters is made to attempt tomaximize function to reduce CO and NOx. In spite of these andcombinations of these attempts to minimize pollutants, fuel combustioncontinues to be a focus of interest to improve fuel efficiency andreduce pollutants.

A fuel additive that includes a combustion catalyst to reduce smoke andparticulate emissions from bus, truck and automobile engines operatingon gasoline fuels would be advantageous. Also advantageous would be afuel additive that increases efficiency and/or decreases pollutants fordiesel fuel applications. It would be advantageous to reduce smoke,particulate and nitrogen emissions from fuel applications. An additivethat does not result in the formation of precipitates would be alsoadvantageous. An additive for hydrocarbon fuel that reduces level of NOxproduced would also be advantageous. Finally, an additive that remainsstable during the combustion process would be advantageous.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a fuel additive comprising amixture of at least one salt and a carrier fluid, the salt comprising[Y]_(a)B_(b)O_(c), wherein [Y] is a cation and the salt is non-acidic,the carrier fluid being operable to maintain the salts within thecarrier fluid in at least a partially dispersed state, the fuel additivebeing operable to enhance combustion when placed into contact with fuelin a combustion zone and combusted, the enhanced combustion beingmeasurable by increased fuel efficiency or decreased pollutant output inan exhaust gas resulting from the combustion of the fuel and the fueladditive. A feature of the present invention is that [Y] is an ammoniumcompound. Alternately, [Y] is an alkali metal.

The present invention also advantageously provides a process forenhancing fuel performance of a hydrocarbon fuel in a combustion systemhaving a combustion zone comprising the steps of providing a fueladditive comprising a mixture of at least one salt and a carrier fluid,the salt comprising [Y]_(a)B_(b)O_(c), wherein [Y] is a cation and thesalt is non-acidic, in an amount effective to enhance fuel performanceto the combustion zone and combusting the hydrocarbon fuel with the fueladditive. A feature of the present invention is that the fuel can be asolid or liquid hydrocarbon fuel.

DETAILED DESCRIPTION

The present invention includes a fuel additive and a method of using theadditive in relation to hydrocarbon fuel. The fuel additive of theinvention includes a boron-containing salt which preferably includes[Y]₂B₄0₇, wherein Y is a cation. Ammonium is a preferred inorganiccation. Alkali metals are another preferred inorganic cation, morepreferably those alkali metals with atomic weights under 50.0.

In one embodiment, the boron salts are at least partially dispersed inwater or another aqueous fluid to create a boron-containing parentdispersion. The boron salts are dispersed in the water or aqueous fluid,and no dissociation or dissolving of the salts occurs. The stabledispersion of boron salts at a preferred particle size of 5 microns orless, more preferably from 2-5 microns, provides a heterogeneouscombustion catalyst in hydrocarbon fuel that provides emissionsreductions and fuel economy improvements.

In an embodiment of the present invention, the boron-containing parentdispersion is added or mixed with a dispersion fluid. The dispersionfluid is a fluid that is operable to maintain the salts within thedispersion fluid in at least a partially dispersed state and that ismiscible, or capable of being maintained in solution, in the hydrocarbonfuel. In a preferred embodiment, the water, for example, is largelyremoved from the boron-containing parent dispersion in the dispersionfluid through thermal means to create the fuel additive. The dispersionfluid is preferably a Group II base oil. Other preferred dispersionfluids include light hydrocarbons, gasoline, polygas, kerosene, diesel,naphtha light oils, Group I, III, IV, V or VI base oils as defined byAPI, aromatic oils, polybutenes, polyglycols, heavier oils orcombinations of the same.

The fuel additive is operable to enhance combustion when placed intocontact with fuel, regadless of the fuel's sulfur content. Enhancedcombustion means that fuel efficiency is increased when compared to fuelwithout the fuel additive, or that pollutant output in an exhaust gasfrom the combustion is decreased, or a combination of these effects.Typical pollutants can include NOx, particulate matter, carbon monoxideand other recognized pollutants resulting from the combustion ofhydrocarbon fuel. It is noted that different geographical regions focuson minimizing a particular pollutant depending on air characteristics.Reduction of a target pollutant or a combination of pollutants, such asNOx and CO, is highly advantageous. Alternately, increased fuelefficiency results in a total lower volume of pollutants, as well aseconomic advantage.

When the fuel additive is prepared using ammonium compounds, ammoniumcompounds are defined as those compounds containing NR_(x) groups, whereR can be for example, hydrogen. NH₄ is particularly preferred. Ammoniumcompounds have been found to have particularly strong catalyticcombustion properties, for example, in terms of NOx reduction, when usedin boron-containing salts in accordance with the present invention.

The borate salts are essentially neutral but more particularly are nothighly acidic. In a preferred embodiment, the boron-containing parentdispersion has a pH between about 6.0 and 8.0. Boric acid is typicallynot present at this relatively neutral pH range. Pentaborates andtetraborates are disclosed herein, for example. The borate salts can bein any form including metaborate, orthoborate or any form of borate thatis not acidic, or combinations thereof. The salts can be eitheranhydrous or in various levels of hydration. The preferred boron saltsaccording to the present invention are inorganic, nonacidic, insolubleand dispersible.

The boron-containing parent dispersion of one embodiment of theinvention can be used in any type of environment, for example, eitherhydrophilic or hydrophobic environments. In the case of a hydrophobicenvironment, it may be necessary that a carrier fluid or fluids beselected to allow for proper dispersion. In a preferred embodiment, thecarrier fluid can be polyoxpropylene monols, diols and polyols,polyoxybutylene monols, diols and polyols, particularly Bayer ActaclearND17. A dispersant used in conjunction with the carrier fluids to createthe fuel additive is also encompassed in a preferred embodiment.Preferred dispersants include polyalkenyl succinimides such as TexacoTFA 4690C, Oronite ODA 78012 and Ethyl Hitec 646. For liquid hydrocarbonfuel applications, at least one carrier fluid can preferably be a fluidwith at least some hydrophilic character that is miscible with the fuelto act as compatibilizing agent in conjunction with dispersant.

The fuel additive of the invention is useful to enhance combustion suchthat more complete combustion is achieved with increased combustion toCO₂ and H₂O as compared to the combustion of the fuel without the fueladditive. The outcome is the reduction of products of partial combustionas well as NO_(x), thereby increasing fuel efficiency.

The fuel additive is used by adding the additive to the fuel in anamount sufficient to increase fuel efficiency and/or to reducepollutants. The terms enhanced and enhanced combustion refer to eitherof these effects. An example of reduced pollutants is a reduction of NOxand CO in an exhaust gas produced from an internal combustion engine ordirect fired open flame burner. Advantageously, both of these effectsare observed though the addition of the fuel additive of the currentinvention. A preferred embodiment includes the addition of between about5 and 10 ppm boron by weight into the fuel though the addition of thefuel additive. Increased amounts of boron up to 25 ppm boron by weightare effective as well. It is notable that a very cost-effective solutioncan be prepared with low weight percent of boron, i.e., less than 20ppm. Another preferred target is less than 15 ppm boron. Relatively lowconcentrations of boron advantageously provide economic benefits, may bemore environmentally acceptable and may provide cleaner operations inthe engine with reduced deposits and residues.

Included in the invention is a process for enhancing fuel performance ofa hydrocarbon fuel in a combustion system including the steps ofproviding the fuel additive described above in an amount effective toenhance fuel performance to the hydrocarbon fuel and combusting thehydrocarbon fuel with the fuel additive. The combustion system can beany means known to those with ordinary skill in the art for combustinghydrocarbon. The combustion system can include any of various internalcombustion engines. In a preferred embodiment, this process is used witha liquid or liquefied hydrocarbon fuel. Alternatively, the process mayalso be utilized with solid hydrocarbon fuel. The result of adding theadditive to the hydrocarbon fuel is an enhanced fuel that has asubstantial amount of hydrocarbon fuel suitable for combustion, and anamount of the fuel additive operable to enhance combustion. Preferably,the enhanced fuel contains boron in an amount operable to reduceemissions and improve efficiency upon combustion of the enhanced fuel ascompared to the combustion of the hydrocarbon fuel without the fueladditive. More preferably, the enhanced fuel contains boron of betweenabout 5 and 10 ppm by weight. Increased amounts of boron up to 25 ppmboron by weight are effective as well. It is notable that a verycost-effective solution can be prepared with low weight percent ofboron, i.e., less than 20 ppm. Another preferred target is less than 15ppm boron.

An alternate embodiment of the invention includes a process forenhancing fuel performance of a hydrocarbon fuel in a combustion systemincluding the steps of adding a chemical addition composition to thehydrocarbon fuel in an amount effective to enhance fuel performance.

The chemical addition composition, also called the dispersion fluid, canbe created by creating an intermediate aqueous parent dispersion bydispersing the borate salt in water. The next step includes combiningthe aqueous boron-containing parent dispersion with a carrier fluid inthe presence of various dispersants, surfactants and the like and thenremoving the water to create the boron-containing dispersion fluid.

The parent solution, or the boron-containing dispersion fluid of theinvention, can be added into or include a combustion fuel. Again, it canbe advantageous to include dispersants to promote dispersion in fuelsthat are hydrocarbon based. Exemplary fuels are kerosene, diesel fueland residual fuels.

An enhanced fuel is created when a substantial amount of a fuel suitablefor combustion is combined with an amount of the boron-containing parentdispersion or the chemical addition composition sufficient to reduceemissions or to increase efficiency upon combustion of the enhancedfuel. Diesel and gasoline are two examples of fuels suitable forcombustion. Other hydrocarbon fuels useful for combustion in acombustion engine are also encompassed. In certain circumstances, thedispersion fluid is a quantity of a target fluid, that is, a fluid thatcontains the desired fuel.

EXAMPLE 1 Preparation of Boron-Containing Aqueous Parent Solution

Charged 83.5 grams of ammonium pentaborate octahydrate (NH₄B₅O₈−8H₂0;mol wt 544.3 grams/mole)) was added to 417.7 grams of deionized water.The mixture was heated with stirring to 80° C. until all of the salt haddispersed. The solution remained clear at 80° C. and contained 1.8%weight boron.

EXAMPLE 2 Preparation of the Boron-Containing Dispersion Fluid

To 1200 grams of a mineral oil basestock, in a 4-liter Erlenmeyer flask,was added 90 grams of Lubrizol 400A, a proprietary additive packagecontaining a mixture of dispersants, and 180 grams of kerosene. Themixture was stirred at ambient temperature until clear solution wasobtained. To the oil solution was added 166.0 grams of theboron-containing aqueous parent dispersion prepared in Example 1. Thetwo solutions were mixed together using a high speed hand mixture toform a water-in-oil emulsion. The emulsion was transferred to a 3-literround bottom flask equipped with agitator and Dean-Starke trap withcondenser. The mixture was heated with agitation to a maximumtemperature of 150° C. over a period of about one hour to remove thewater. The result was a dispersion of the borate salt in the oil matrix.The final water content was 6,480 ppm with a final theoretical boroncontent of 1,827 ppm.

EXAMPLE 3 Preparation of Boron-Containing Two Cycle Engine FuelTreatment

A lubricating oil suitable for dilution with gasoline and use as twocycle engine fuel was prepared by mixing the boron containing dispersionfluid of Example 2 with Tufflo 6036, a proprietary additive packagecontaining various detergents and dispersants to a final boron contentof about 300 ppm. Fuel was then added to the mixture at a 50:1 ratio toprovide a final boron content of about 6 ppm.

EXAMPLE 4 Homelite Yard Broom II Leaf Blower Test

The Homelite Yard Broom II Leaf Blower is a hand held blower that uses a30 cc two cycle gasoline engine. The leaf blower is used to screen forengine efficiency improvements, especially increased fuel economy. Toestablish a baseline, the standard Homelite two cycle oil was mixed 50:1with regular unleaded gasoline of 87 octane. Exactly 250 milliliters ofthe fuel mixture was added to the leaf blower fuel tank. The engine wasthen run at full RPM until the fuel was totally consumed and the enginedied. The run time, RPM and exhaust temperature were measured andrecorded. The test was repeated using the boron-containing oil fromExample 3 at 50:1 dilution and about 6 ppm boron. The result was anincrease in RPM of 2.3%, a decrease in exhaust air temperature of 6.5%and an increase in run time of 11.8%. These values demonstrate asignificant improvement in engine operation efficiency with theboron-containing oil of the invention.

EXAMPLE 5 Diesel Fuel Combustion in an Open Flame

A diesel fuel fired open flame burner was used to measure CO emissions.A baseline was established by burning untreated diesel at specific andcontrolled fuel and air mixtures. For this test the fuel:air mixture wasnot varied. The boron dispersion fluid of Example 2 was diluted to 20ppm B with high sulfur No. 2 diesel. This mixture was then used to fuelthe burner and over 14 measurements a reduction in CO of 11.5% wasmeasured.

1. A fuel additive comprising a mixture of at least one salt and acarrier fluid, the salt comprising [Y]_(a)B_(b)O_(c), wherein [Y] is acation and the salt is non-acidic, the carrier fluid being operable tomaintain the salt within the carrier fluid in at least a partiallydispersed state, the fuel additive being operable to enhance combustionwhen placed into contact with fuel in a combustion zone and combusted,the enhanced combustion being measurable by increased fuel efficiency ordecreased pollutant output in an exhaust gas resulting from thecombustion of the fuel and the fuel additive.
 2. The fuel additive ofclaim 1 wherein the salt is selected from the group consisting ofmetaborate, pentaborate, tetraborate and orthoborate and combinationsthereof.
 3. The fuel additive of claim 1 further comprising [NH₄]₂B₄O₇.4. The fuel additive of claim 1 further comprising an ammonium compound.5. The fuel additive of claim 1 wherein the pH of the solution isbetween about 6.0 and 8.0.
 6. The fuel additive of claim 1 wherein thesalt is inorganic.
 7. A process for enhancing fuel performance of ahydrocarbon fuel in a combustion system having a combustion zonecomprising the steps of providing the fuel additive of claim 1 in anamount effective to enhance fuel performance to the combustion zone andcombusting the hydrocarbon fuel with the fuel additive.
 8. The processof enhancing fuel performance of claim 7 wherein the hydrocarbon fuel isa liquid hydrocarbon fuel.
 9. The process of enhancing fuel performanceof claim 7 wherein the hydrocarbon fuel is a solid hydrocarbon fuel. 10.The process of enhancing fuel performance of claim 7 wherein thecombustion zone is within an engine operating on gasoline fuel.
 11. Theprocess of enhancing fuel performance of claim 7 wherein the combustionzone is within an engine operating on diesel fuel.
 12. The process ofenhancing fuel performance of claim 7, wherein the fuel additive isoperable to enhance combustion when placed into contact with fuel in adirect fired burner or open flame in the combustion zone and combusted,the enhanced combustion being measurable by increased fuel efficiency ordecreased pollutant output in an exhaust gas resulting from thecombustion of the fuel and the fuel additive.
 13. An enhanced fuelcomprising a substantial amount of hydrocarbon fuel suitable forcombustion, and an amount of fuel additive of claim 1 operable toenhance combustion.
 14. The enhanced fuel of claim 13 wherein boron ispresent in the hydrocarbon fuel in an amount of between about 5 and 10ppm by weight.
 15. The enhanced fuel of claim 13 wherein the amount offuel additive is the amount operable to reduce emissions upon combustionof the enhanced fuel as compared to the combustion of the hydrocarbonfuel without the fuel additive.
 16. The enhanced fuel of claim 13wherein boron is present in the hydrocarbon fuel in an amount less thanabout 25 ppm by weight.
 17. A process for creating an enhancedhydrocarbon fuel for use in a combustion system comprising the step of:adding an amount effective to enhance fuel performance to thehydrocarbon fuel of a chemical addition composition, the chemicaladdition composition comprising the product from the dispersion of anon-acidic borate salt in water.
 18. The process of claim 17, whereinthe salt is inorganic.
 19. A process for creating a fuel additive forenhancing combustion of a hydrocarbon fuel, the process comprising thesteps of: adding the salt [Y]_(a)B_(b)O_(c), wherein [Y] is a cation andthe salt is non-acidic, to a fluid to at least partially disperse thesalt in the fluid to create a boron-containing parent dispersion; mixingthe boron-containing parent dispersion with carrier fluid such that theboron-containing parent dispersion is generally dispersed in the carrierfluid; and removing a substantial portion of the fluid from the mixtureof the boron-containing parent dispersion with the carrier fluid tocreate a fuel additive that is operable to enhance combustion when addedto a combustion zone in the presence of a hydrocarbon fuel andcombusted.
 20. The process of claim 19, wherein the salt is inorganic.